Transcript for Officer Felt Heartsick After Firing on Runaway Family Van

The situation on a new mexico highway escalated quickly. A mother, tuled over by state troopers for speeding while driving a minivan full of kids. And then real time decisions as the nightmare on both sides camed to a climax with gunfire. You're about to meet the man who lost his job in the faceoff. And find out why he wants the world to know what he says is the full story. Here's ryan owen. Get out of the vehicle! Get out of the vehicle right now! It's the traffic stop that outraged so many for many reasons. A mom stopped for speeding in her minivan with five children inside keeps taking off on police. One of those children, her 14-year-old son even scuffles with an officer. Open the door! Later, that same officer bashes in the passenger window. A backoff officer fires three shots at that minivan packed with kids between the ages of 6 and 16. So this is you here? Yes. Reporter: Those shots cost him his job with new mexico state police. The 12-year veteran with the force says he pulled up on the traffic stop long after it's ka lated and said he had no idea there were children inside that minivan with dark tinted windows. When you find out there were children in that minivan, what did you think? Well, I -- my heart sank. I was on the passengered a that time, seeing them get out at gun point again, I couldn't believe there were that many children. Did you second guess your decision? No, because I thought I did what was correct at that time. He said all dispatch told him was to respond to an unruly driver. Approach on the left hand side, all I see is a bunch of heads. What went through my mind is that we're outnumbered. Reporter: When the driver started to flee yet again, the 53-year-old said he lined up with the line on the road and shot at the tire. I know you say you're aiming at the tire, but that tire is connected with a vehicle that had an awful lot of people in it. Why would you fire at a vehicle that knows has a lot of people in it. I'm not shooting at human being. I'm shooting at a tire. He missed the tire and the mom and five kids were off again, this time leading cops on a chase that reached speeds of 100 miles an hour. Get out! Get on the ground right now! Reporter: When it finally ended, officers arrested the driver, a 39-year-old of connecticut and charged her with child abuse and fleeing police. She said she's not guilty and did what she did that october day to protect her children. She's a self-described empowerment coach who gives parenting advice. And a recording artist who uploads her music videos to youtube. Pick at the jackson wounds and rubbing in the michael vick. Reporter: Today, we returned to the scene of that routine traffic stop that turned out to be anythbut. Montoya was the only one of the three officers fired for his actions that day. Other two, including the officer who broke the window are back on the street. Here in taos, many believe he should be back with them. I believe in him. I think he's the honest, most caring person. They describe a veteran officer who was never dref, certainly never trigger happy. This was the first time he fired in tine of duty. I believe justice has been done. He's a good man. Here, the man known nationally as the cop who shot at a minivan full of kids is better known as a youth referee. It's unfathomable that he lost his job especially in light of the fact that there had been other instances where similar incidents were justified. The use of deadly force has to be used only when you are being threatened by deadly force. Right there. That's his discharge. This was a horrible car stop by all participants. Nicholas cosell is formerly with a police department. Who was a danger to him? He says montoya had no business trying to shoot out that tire. Him shooting a tire of a vehicle moving away from him, the tire in the year is exposed about the size of a dollar bill. He has the ability to shoot that tire, he should be in the olympic team. When I moved over, I could see well in front of me. There was no vehicle in front of that vehicle either going or coming. So I believe I had the right to try and detain that situation there. And that's how come I shot at the tire. Montoya is appealing his determination, but knows getting his badge and especially getting his gun back, that's an uppill battle. Can the public trust your judgment after you fired on a mi minivan with kids in it. I'm not one to take my handgun out of my holster in every little situation. Do you want to live in a world where police officers are firing routinely at vehicles with weem in them when they' been fulled over for speeding? Does that world make sense to you? No, it does not make sense. No, and if I knew there was even one child in that vehicle, i wouldn't have done it. I'm ryan owens for "nightline" in taos, new mexico.

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